Established 55 gallon planted tank with 7 Columbian Tetras, 7 Tiger Barb's, 5 Brass/Gold Tetras, 4 Panda Garras, 5 Yoyo Loaches, 2 plecos, 1 Pea Puffer and a dwarf Petricola catfish. I had a dwarf Orange Mexican Cray Fish but last week he mysteriously died. Today I noticed the Pea Puffer repeatedly attacking the top fin of the Columbian Tetras, non stop. And to my surprise the Tetras didn't attack back, they only 'jumped' away (swam fast away). This stocking config is a solid year old, why now aggression and should I remove the Puffer?